As more mobile applications hit stores, one researcher believes the number of downloads will skyrocket.

In 2015, the total number of mobile-application downloads is expected to reach nearly 48 billion, research firm In-Stat reported today. The company said that the growth in downloads will be due mainly to the growing popularity of touchscreen-equipped smartphones. According to In-Stat, touchscreens will be available on approximately 90 percent of all smartphones shipped this year, and that number could hit nearly 100 percent in the next several years.

It also helps that the smartphone business is booming. In 2010, smartphones accounted for 23 percent of all phone shipments. In 2015, In-Stat expects that figure to grow to 45 percent of all phone shipments.

Yesterday, Apple announced that it now has over 425,000 applications available in its App Store, including 90,000 designed for the iPad. Since the App Store's launch in 2008, iOS users have downloaded more than 14 billion apps, helping developers earn a whopping $2.5 billion.

While Apple might be the biggest player in the mobile-app market right now, it's not alone. The Android Market, for example, has 200,000 free and paid applications available, according to data Google touted last month. At that point, 4.5 billion applications had been downloaded from that marketplace. Research In Motion and Microsoft, among other providers, have mobile app stores, as well.

According to In-Stat, however, those running iOS or Android are "significantly more likely" to download applications to their devices than those running other operating systems.